Continuous-conveyer bake oven



Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

JAMES C. WOODSON, OF EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC 8:; MANUFACTURING COMPANY, A CORPORATION OF PENNSYL-VANIA.

CONTINUOUS-GONVEYER BAKE OVEN.

Application filed October 27, 1923. Serial No. 671,172.

To all whom it may concern:

Be it known that I, J AMES C. Woonson, a citizen of the United States,and a resident of East Pittsburgh, in the county of Allegheny and Stateof Pennsylvania, have invented a new and useful Improvement inContinuous-Conveyor Bake Ovens, of which the following is aspecification.

My invention relates to ovens and particularly to ovens of theventilated type.

One object of my invention is to provide a relatively simple means forregulating the amount of ventilation provided in ovens of the continuousconveyer type.

Another object of my invention is to pro vide a relatively simple meansfor effecting an air seal at the open end of a continuous conveyer-typeoven to prevent the air from escaping outwardly therethrough.

In practicing my invention, I provide a plurality of walls ofheat-insulating material enclosing a baking chamber and a returnchamber, and having a continuous conveyer traversing both chambers. Oneof said walls is provided with an opening to permit of placing materialon, and of removing it from, said conveyor. A heatlng means, preferablya plurality of electrlc resistor members, is located in said bakingchamber.

A conduit is provided to connect the return chamber with the outsideair, a part of said conduit being subjected to heat from said bakingchamber. A second conduit is connected to the baking chamber itself andalso to the first named conduit and suitable dampers are provided forboth conduits.

In the single sheet of drawings,

Figure 1 is a view, in vertical longitudinal section, of an ovenembodying my invention,

Fig. 2is a View partially in plan and partially in horizontal section,of a part of the oven illustrated in Fig. l and Fig. 3 is a view, in endelevation, of the oven illustrated in Figs. 1 and 2.

An oven structure, designated by the numeral 11, comprises a pluralityof outer walls 12, a floor 13 and a roof wall 14, together with sidewalls that are not particularly illustrated in the drawing; all of saidwalls being constructed of suitable heatinsulating material.

The oven structure 11 may be of any suitable or desired contour and sizeand is here I illustrated as beingsubstantially rectangular in section.

A baking chamber 15', of substantially rectangular-contour is located inthe intermediate or central portion of the oven structure 11 and isdefined by a plurality of end walls 16 of a suitable refractoryheatinsulating material and a floor 17, in compending refractory bafileplates 19 may be.

provided to further insulate the return chamber from the baking chamberand to prevent the interchange of air between the two chambers.

A continuous conveyer mechanism for the oven structure 11 comprises anysuitable means, such as a plurality of chains 21 located in spacedrelation and moving over a plurality of spaced pulleys 22 located in theupper part of the furnace structure 11 and a plurality of spaced pulleys23 located in the intermediate part of the structure within the lowerpart of the baking chamber 15.

A plurality of similar pulleys 22 are located in the lower orintermediate portion of the return chamber 18 upon which the chains maymove. A plurality of swinging trays 24 are suitably connected to thechains 21, and material to be baked or otherwise heat treated may beplaced upon the respective trays 24. An opening 25 is provided at oneend of the furnace structure 11 in one or both of the end walls 12 topermit of placing material on or of removing it from the trays.

A plurality of heating elements 26, of any suitable or desired type arelocated within the baking chamber 15, preferably supported by the floorthereof. As any suitable or desired type of heating means may beemployed, the heating means is here illustrated schematically only.

Vith the hereinbefore described construction of an inner baking chamberand of an outer return chamber, there would be a tendency for heated airto flow outwardly through the material-receiving opening 25 and in orderto prevent this, I provide a novel 'entilating system comprising aplurality of conduits 27 that are located at the two sides of the ovenstructure 14 and are operatively connected bysuitable,horizontally-extending portions with the return chamber 18 at itsintermediate portion.

\Vhen the oven is in operation,- the tem perature of the air Within thebaking chamber isrelatively high, and the temperature of the air Withinthe return chamber will also be high, but not as high as in the bakingchamber, The heated air located in the return chamber will, therefore,flow out of the return chamber and into the substantially verticallyextending conduits 27 connected thereto, thereby drawing 'air inwardlythrough the material receiving opening 25. This provides, therefore, anair seal at the opening and eitectively prevents heated air located inthe return chamber 18 from flowing outwardly through the opening, andreducing the efticiency of the oven. The inner walls of the conduits 27may be made relatively thin and be heated by the air in the bakingchamber 15, thereby causing a still greater ventilating eflect.

If it is desired to provide ventilation for the baking chamber itself,as may be necessary, for instance, in drying or baking japannedarticles, I provide a plurality of conduits '28, one end of each ofwhich extends through the roof portion 14 into the baking chamber 15.The other end of the conduits 28 may be connected to a horizontallyextending conduit portion 29 that has its ends connected to the twovertically extending conduits 27. Dampers 31 may be employed in therespective conduits 27 and 28 to adjust the amount of air that ispermitted to flow through them.

It is evident that heated air in the baking chamber 15 will flowoutwardly through the conduits 28 and thereby cause an additionalamount-of air to enter the opening 25 flowing first downwardly past thelower end of the bafiie'plate 19 and then ast the upper end of the sideWalls 16 of the baking chamber.

Wherever it is necessary to provide ventilation in an oven of thecontinuous conveyer type, such as in japanning ovens, the deviceembodying my invention provides a relatively simple means for efi'ectingor providing an air seal at the receiving opening or openings, and alsoresults in an increased thermal etficiency of the entire oven.

Various modifications and changes may be made without departing from thespirit and scope of the invention and I desire, therefore, that onlysuch limitations shall be placed thereon as are imposed by the prior artor are set forth in the appended claims.

I claim as my invention:

1. In an oven, the combination with a plurality of walls enclosing abaking chamber, a return chamber located outside of said bakingchamber,- one of said Walls having an opening therein ror access intosaid return chamber and a hcatin means in said baking chamber, of meanstor causing air to flow into said return chamber through said opening.

2. In an oven, the combination with a plurality of walls enclosing abaking chamber, a return chamber located outside of said baking chamber,one of said walls having an opening therein for access into said returnchamber, and a heating means in said baking chamber, of means foreffecting an air seal at said opening.

3. In an oven, the combination with a plurality of walls enclosing abaking chamber, a return chamber located outside of said baking chamber,one of said Walls having an opening therein for access into said returnchamber, and a heating means in said. baking chamber, of means,comprising a conduit connection to said return chamber, for causing airto flow throughsaid opening, into said return chamber and out throughsaid conduit connection.

4. In an oven, the combination with a plurality of Walls enclosing abaking chamber, a return chamber, located outside of said bakingchamber, one of said walls having an opening therein for access intosaid return chamber and a heating means in said baking chamber, or meansfor causing air to flow into said return chamber through said opening,and means for regulating the amount of air flowing into said opening.

5. In an oven, the combination with a plurality of walls enclosing aninner baking chamber and an outer return chamber, of substantiallyU-shape, one of said walls having an opening therethrough, and heatingmeans in said baking chamber, of means comprising a conduit operativelyconnected to said return chamber for permitting air to flow through saidopening into said return chamber and out through said conduit and asecond conduit operatively connecting said baking chamber and said firstconduit to cause air to enter said opening and flow through a portion ofsaid return chamber and of said baking chamber and out through saidconduit.

6. In an oven, the combination With a plurality of Walls enclosing abaking chamber and a return chamber, one of said Walls having an openingtherethrough, and heating means in said baking chamber, of means 10energized by the heat generated by said heating means for causing air toflow inwardly through said opening to provide an air seal therefor.

In testimony whereof, I have hereunto subscribed my name this 20th dayof October, 1923.

JAMES C. WOODSON.

